Purification materials and method of filtering using the same

ABSTRACT

The invention relates to a purification material ( 1 ) comprising filtration particulate matter aggregated with a first binder and further processed with a second binder to generate a porous fluid filtration material or a non-pourous coating, a filtering device comprising a housing ( 11 ) and the purification material ( 1 ), and a method of filtering and/or purifying a fluid including water or other solutions containing chemical and microbiological contaminants, such as fluids containing heavy metals, pesticides, by products of oxidation chemicals and including cysts, bacteria and/or viruses, where the fluid is passed through ot made to contact a surface of the purification material ( 1 ).

FIELD OF THE INVENTION

This invention relates generally to the field of solution and fluidfilters or purification devices, primarily to aqueous solution filtersand water purification, devices for gases and water and other aqueousliquids, which remove contaminants from the gas or aqueous liquidsolution passed through them. In its more particular aspects, theinvention relates to the field of such devices that remove chemical andmicrobiological contaminants, including pesticides, byproducts ofchemical treatment processes, cysts, bacteria and viruses and theircomponents, from water or aqueous solutions.

BACKGROUND OF THE INVENTION

Purification or filtration of water or other aqueous solutions isnecessary for many applications, from the provision of safe or potabledrinking water to biotechnology applications including fermentationprocessing and separation of components from biological fluids.Similarly, the removal of microbial organisms from breathable air inhospitals and clean rooms, where ultrapurified air is required, and inenvironments where the air will be recirculated, such as aircraft orspacecraft, is also an important application for filtration media. Inrecent years, the need for air filtration and purification in the homehas become more recognized, and the competing concerns of energyefficiency and indoor air quality have lead to numerous air filtrationproducts, such as HEPA filters and the like, that purport to removesmall particles, allergens, and even microorganisms from the air.

There are many well-known methods currently used for water purification,such as distillation, ion-exchange, chemical adsorption, filtering orretention, which is the physical occlusion of particulates. Particlefiltration may be completed through the use of membranes or layers ofgranular materials, however in each case the pore size of the materialand the space between the granular materials controls the particle sizeretained. Additional purification media include materials that undergochemical reactions, which alter the state or identity of chemicalspecies in the fluid to be purified.

In most cases a combination of techniques are required in order tocompletely purify fluids, such as water. Combinations of technologiesmay be implemented by combining functions in a single device or usingseveral devices in series where each performs a distinct function.Examples of this practice include the use of mixed resins that removeboth negative and positively charged chemical species as well as specieswithout charge.

Many of these fluid purification techniques and practices are costly,energy inefficient and/or require significant technical know-how andsophistication. Traditional means of reducing these complicationsrequire extensive processing or specially designed apparatus.Unfortunately, development of low cost techniques do not adequatelyaddress the removal of harmful chemical and biological contaminates,such as, bacteria and viruses. For example, simple point-of-usepurification devices, such as filters attached to in-house water supplyconduits or portable units for campers and hikers, cannot sufficientlyremove bacteria and viruses unless relatively costly membrane technologyor strong chemical oxidizers, such as halogens or reactive oxygenspecies, are utilized.

The Environmental Protection Agency (EPA) has set forth minimumstandards for acceptance of a device proposed for use as amicrobiological water purifier. Common coliforms, represented by thebacteria E. coli and Klebsiella terrigena, must show a minimum 6-logreduction, 99.9999% of organisms removed, from an influent concentrationof 1×10⁷/100 ml. Common viruses, represented by poliovirus 1 (LSc) androtavirus (Wa or SA-11), which show resistance to many treatmentprocesses, must show a minimum 4 log reduction, 99.99% of organismsremoved, from an influent concentration of 1×10⁷/L. Cysts, such as thoserepresented by Giardia muris or Giardia lamblia, are widespread,disease-inducing, and resistant to chemical disinfection. Devices thatclaim cyst removal must show a minimum 3 log reduction, 99.9% of cystsremoved, from an influent concentration of 1×10⁶/L or 1×10⁷/L,respectively. The EPA has accepted the use of other particles in theappropriate size range as a means of testing devices that claim thisfunction.

Materials that are highly efficient at removing and immobilizingmicrobial organisms have numerous applications, but a particular area ofapplication is in the biotechnology and fermentation industries. Notonly would such materials be useful in the processing of fermentationbroth for recycling or reuse, they also would have utility as microbialimmobilization materials for the microbes of interest to thefermentation process.

It is well known to use granular, particulate, or fibers of natural orsynthetic materials for fluid treatment. These materials are commonlyused singularly and in mixtures. In some cases a material whichimmobilizes the individual particles or fibers together, referred to asa binder, is used. Techniques for generating porous blocks of carbonusing a polymer binder is described in prior art by companies such as KXIndustries, Amway Corporation, and Cuno.

Natural materials used in filter applications include carbonaceousmaterials such as activated carbon and minerals such as apatites,oxides, hydroxides, phosphates, and silicates and combinations thereof.

Synthetic materials used in filter applications include hydrocarbonpolymers, and mineral species such as apatites, oxides, hydroxides,phosphates, and silicates and combinations thereof.

The particle size of the filtration material used in filtration devicescontrols many of the technical specifications and successful applicationof a filtration device. Particle sizes commonly used include those in arange between 80 and 325 mesh. Grinding and milling of both natural andsynthetic materials can be required to generate particles in this sizerange. Although particle sizes outside this range can be used theypresent practical problems. As example, small particles such as thosesmaller than 325 mesh are difficult to retain in the filtration devicewhile particles larger than 80 mesh lack the needed surface area formany applications.

The grinding and milling of natural and synthetic materials oftenproduces particles of varying size and distribution. Particles sizedistributions and mixtures of distributions are modified by sieving,particle collection, and recombination. Particle sizes that are toosmall for use in filtration devices often go to waste or must be leftfor other applications.

It is also common for synthetic materials to be synthesized in particlesizes that are too small for use in many filtration devices.

The use of soluble treatment chemicals for increasing particulate mattersize in water and waste water treatment is well known. It is commonlyunderstood that inorganic and organic materials can be used toflocculate, coagulate, and aggregate small particulate material found ina water stream. The resulting larger particles are now able to befiltered or to be removed from the water system through standardsedimentation and clarification methods. It is also well understood thatmany particulates in the water stream carry positive or negative chargesand that this characteristic may be used to aggregate the smallparticles into larger species.

Accordingly, there remains a need in the art of fluid filtration for anuncomplicated, safe, inexpensive fluid purification and filtrationmethod and device incorporating insoluble small filtration particles(<325 mesh) and soluble water treatment chemicals. It is the intentionof this invention and art to generate filtration particulate materialand filtration devices through the use of multiple different chemicalbinders. Furthermore it is the intention of this invention and method topermit the simultaneous use of activated carbon, silicates, oxides,metal hydroxides, and phosphates in the forms which are readilyavailable and commonly found or synthesized by a variety of differentmethods. There is also a need in the art for a method and device thatcan address the EPA requirements for designation as chemical andmicrobiological water purifiers, such that the device is more thansuitable for consumer and industry point-of-use and point-of-entryapplications.

SUMMARY OF THE INVENTION

To this end, the present inventors have discovered that a significantproblem in the known use of small particulate inorganic and organicmaterials, called fines, incorporated into filter devices is that theparticles are difficult to contain thus requiring very small pore sizecontainers which increases the back pressure of devices. Small particlesalso tend to plug devices which leads to short product lifetimes. Lossof particulate material decreases or inhibits product performance, cancause illness, and presents a general annoyance for devices users.Finally, as with all particulate containing devices, grinding ofparticles as a result of particle movement generates even smallerparticles.

Additionally, the present inventors have discovered that there alsoexists a significant problem in the known binding methods used togenerate filter devices. As the size of the filtration particlesdecreases an increase in the amount of polymer binder is required inorder to retain and immobilize the particles. The increase in binderlevels required often generates filtration blocks with small pores whichincreases device backpressure.

The invention disclosed provides a means for using small filtrationparticulate matter (<325 mesh), material fines, generated from theprocessing of natural or synthetic materials or from the synthesis ofmaterials for the generation of porous blocks suitable for fluidfiltration.

The invention in general involves the use of multiple organic and/orinorganic binders to first increase the particulate matter size, andsubsequently to generate porous blocks or sheets or coatings. Non-flowthrough coated surfaces which function by contact filtration are alsoconsidered an important material that may be used in the invention.

The method of the invention involves two steps. The first step involvestaking small particles or fines in the size range between 10 nanometersand 200 microns and aggregating or agglomerating them into largerparticles through the use of positively charged, negatively charged,and/or uncharged organic or inorganic polymers, and/or compounds such asoxides, hydroxides, phosphates, and silicates. Examples of suitablebinders include, polyelectrolytes such as polyamines, polyalcohols,polysaacharides, polyacrylates, polyacrylamides and derivitized naturaland synthetic polymers, oxides of magnesium and calcium, and hydroxidesof calcium, magnesium, aluminum, and iron. Additionally, precipitationof hydroxide and phosphate compounds may be used.

This first processing step may also include mechanical steps, such asmixing, spraying, dripping or fluidic processing. This step may alsoinclude heat treatment, including digestion, calcining, sintering, andfiring. The chemical and physical processing of this step may berepeated until the particles are of appropriate size, which is usuallygreater than 325 mesh. It should be understood that during the firststep of the invention, the binder may be partially or fully removed bythe various processing methods.

The second step in the invention involves taking the particulatematerial generated in step 1, particles of significantly greater size,and combining them with a second binder, of different type, whichimmobilizes the particles into a porous block. This second step mayutilize standard techniques such as extrusion, molding, and pressure.

The invention and method provides an efficient means of using smallparticles which are difficult to implement in the generation offiltration devices.

There are numerous advantageous to the method of this invention. First,the initial starting particles have very large surface areas whichincreases the filtration efficiency of the filtration device when theyare included as components of larger particles which are now retained inthe device.

Second, the invention provides the ability to simultaneously use amixture or agglomeration of different filtration particle types. As anexample, carbon, apatite, silicate, metal oxide, hydroxide, and/orsulfur containing particles may be agglomerated to generate a mixedcomposition particle.

Third, the method provides a means of producing insoluble watertreatment polymer materials from previously soluble polymeric compoundsand retaining them in the filtration device. As an example, highmolecular weight charged water treatment polymers have a plethora ofactive binding sites. By using some of the active binding sites to bindparticulate material the polymer is rendered insoluble. Since only someof the many active binding sites are used for particle binding therestill remains many active binding sites which are now available forparticipating in the fluid stream filtration, for the removal ofchemical and biological contaminants.

Fourth, the method allows the use of materials that are hazardous inlarger sizes such as magnesium containing silicates in asbestos form tobe used in safer smaller particulate sizes.

Fifth, the method provides a means for utilizing nanometer sizeparticles of metals and metal oxides that are of interest in fluidcatalysis and chemical stream processing.

It should be understood that the present invention may also be used forgenerating particles in a size range greater than 100 mesh.Unfortunately, the effectiveness of filters generated with largermaterials with or without a binder is compromised by channeling andby-pass effects caused by the pressure of fluid, in particular, waterand aqueous solutions, flowing through the filter media as well asparticle erosion and aggregation. Because many chemicals, viruses andbacteria are removed by intimate contact with the adsorption material,even relatively small channels or pathways in the granular materialformed over time by water pressure, water flow, particle erosion, orparticle aggregation are easily sufficient to allow passage of theundesirable chemical and microbiological contaminants through thefilter.

For example, taking water as an exemplary fluid and using the materialof the invention as a filtration medium for microbial organisms,calculations based on a virus influent concentration of 1×10⁶/L showthat where a 4-log reduction is to be expected, only a 3.7 log reductionactually occurs if only 0.01% of the water bypasses treatment by passingthrough channels formed in the filter media during filtration. If 0.1%of the water passes through untreated, then only a 3 log reductionoccurs. If 1% passes through untreated, only a 2 log reduction occurs,and if 10% passes untreated, only a 1 log reduction occurs. Where a6-log reduction is expected, the detrimental results of channeling areeven more dramatic, with only a 4-log reduction actually occurring when0.01% of the water bypasses treatment. This invention solves thisproblem by providing a method and device for removing contaminants,including chemicals, bacteria and viruses, where very small particulatefiltration materials and device adsorptive filter media are immobilizedwith multiple chemical binders material to form a porous filter materialthat eliminates the possibility of channeling and active materialby-pass.

This invention is, in general, a device and method for the purificationand filtration of aqueous fluids, in particular water (such as drinkingwater or swimming or bathing water), or other aqueous solutions (such asfermentation broths and solutions used in cell culture), or gases andmixtures of gases, such as breathable air, found in clean rooms,hospitals, diving equipment homes, aircraft, or spacecraft, and gasesused to sparge, purge, or remove particulate matter from surfaces. Theuse of the device and method of the invention results in the removal ofan extremely high percentage of microbiological contaminants, includingbacteria and viruses and components thereof as well as chemicalcontaminants such as heavy metals, pesticides and by products ofchemical treatment processes. In particular, the use of the device andmethod of the invention results in purification of water to a level thataddresses the EPA standards for chemical or microbiological waterpurification.

In one embodiment, the invention relates to a purification material forfluids that contains particulate carbon that is in the form of a porousblock as the result of employing multiple binders. Typically, at least aportion of this carbon is activated and from natural sources.

In another embodiment, the invention relates to a purification materialfor fluids that contains particulate apatite minerals that is in theform of a porous block as the result of the presence of the multiplebinders. Apatites are commonly mined, prepared from natural sources(bone char), or synthesized from calcium and phosphorus containingcompounds.

In another embodiment, the invention relates to a purification materialfor fluids that contains particulate oxide and hydroxide minerals thatare in the form of a porous block as the result of the presence of themultiple binders. Aluminum, iron, and magnesium oxides are commonlymined and purified from natural sources (alumina/bauxite, chlorides), orsynthesized from aluminum, magnesium containing minerals, or generatedfrom synthetic sources such as the mixing of aluminum, iron, andmagnesium containing compounds.

In another embodiment, the invention relates to a purification materialfor fluids that contains particulate silicate minerals that are in theform of a porous block as the result of the presence of the multiplebinders. Aluminum, calcium, iron, magnesium, sodium, and potassiumcontaining silicates are commonly mined and purified from naturalsources, or synthesized from aluminum, calcium, iron, magnesium, sodium,or potassium containing compounds.

In another embodiment, the invention relates to a purification materialfor fluids that contains particulate metals important in catalysis thatare in the form of a porous block as the result of the presence of themultiple binders. Platinum group metals, such as platinum, rhodium, andpalladium, as well as coinage metals, such as gold, silver, copper, andnickel, as well as heavy metals, such as cadmium and chromium, arecommonly mined and purified from natural sources, or reclaimed fromspent electronic components.

In another embodiment, the invention relates to a purification materialfor fluids that contains a mixture of the particulate filtrationmaterials described in the individual embodiments of this invention thatare in the form of a porous block as the result of the presence of themultiple binders. The mixtures included in this embodiment can varydramatically with individual components included varying from less than1% through greater than 99%.

In yet another embodiment, the invention relates to a purificationmaterial for fluids that contains a mixture of particulate filtrationmaterials generated by combining particulate material generated by amethod consistent with the first step of this invention with materialsthat have been generated through traditional methods, such as grindingand or milling. The mixture of particles is then processed into the formof a porous block as the result of the presence of the binders andmethod consistent with the second step of the method. The mixtures ofparticles generated in the different processes included in thisembodiment can vary dramatically with individual components includedvarying from less than 1% through greater than 99%.

Also typically, the binders used are inorganic or organic compoundsincluding polymeric or oligomeric materials that are capable ofmaintaining the particulate material in a particulate form (firstbinder) and in block structure form (second binder). This allows thepurification material to be extruded, molded or pressed into any desiredshape, e.g., a shape suitable for inclusion into the housing of afiltration device, which provides for fluid inflow and outflow, andwhich filtration device has one or more chambers for contact of thefluid with the purification material. Such a device forms anotherembodiment of the invention. In addition to maintaining the filtrationparticles immobilized in a unitary block, the polymeric binders alsoprovide desirable physical characteristics to the filter material, e.g.,rendering it rigid or flexible, depending upon the type and amount ofpolymeric binders used.

In another embodiment, the invention relates to a purification materialfor fluids that is in the form of a self-supporting sheet or membranecontaining the particulate filtration immobilized with the binders.

In another embodiment, the invention relates to a purification materialfor fluids that is in the form of a porous coating supported by a poroussubstrate containing the particulate filtration immobilized with thebinders.

In another embodiment, the invention relates to a purification materialfor fluids that is in the form of a nonporous coating supported by aporous or nonporous substrate containing the particulate filtrationimmobilized with the binders. Here the fluid is filtered by surfacecontact.

The invention also relates to methods of filtering fluids, such aswater, aqueous solutions, and gases, to remove a large proportion of oneor more types of chemicals, microorganisms contained therein, bycontacting the fluid with the purification material of the invention. Ina particular aspect of this embodiment of the invention, this contactingoccurs within the device described above, with the unfiltered fluidflowing through an inlet, contacting the purification material in one ormore chambers, and the filtered fluid flowing out of the chamber throughan outlet.

The purification material of the invention can be used to purifydrinking water, to purify water used for potable and/or recreationalpurposes, such as in swimming pools, hot tubs, and spas, to purifyprocess water, e.g. water used in cooling towers, to purify aqueoussolutions, including, but not limited to, blood, fermentation broths,and cell culture solutions (e.g., for solution recycling in fermentationor other cell culture processes) and aqueous fluids used in surgicalprocedures for recycle or reuse, and to purify gases and mixtures ofgases such as breathable air, for example, air used to ventilatehospital or industrial clean rooms, air used in diving equipment, or airthat is recycled, e.g., in airplanes or spacecraft, and gases used tosparge, purge or remove volatile or particulate matter from surfaces,containers, or vessels. The purification material of the invention hasthe additional advantage of making use of readily available filtrationmaterials and more especially small particulate materials, includingthose obtained from natural and synthetic sources, while stillmaintaining high purification efficiency.

In yet another embodiment of the invention, the materials of theinvention, namely small filtration particulate matter and optionallyother adsorptive materials with a multiple binder matrix and which isformed into a block or sheet or coating, can be used as animmobilization medium for microorganisms used in biotechnologyapplications such as fermentation processes and cell culture. In thisembodiment, biological process fluids, such as nutrient broths,substrate solutions, and the like, are passed through or over theimmobilization material of the invention in a manner that allows thefluids to come into contact with the microorganisms immobilized thereinand thereon, and effluent removed from the material and furtherprocessed as needed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a particular embodiment ofthe invention, namely a water filter housing containing a block filterincorporating synthetic apatite minerals and granulated activatedcharcoal (GAC) in a multiple binder matrix according to the invention.

FIGS. 2 a and 2 b are schematic views of a particular embodiment of theinvention, namely a filter material containing synthetic apatiteminerals and granulated activated charcoal (GAC) and a multiple bindermatrix in the form of a membrane or sheet.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, one embodiment of the invention relates to apurification material in the form of a block filter containinggranulated carbon, such as activated carbon, and synthetic or naturalapatite (hydroxy-calcium-phosphate) with a first binder to increasefiltration particle size and a second binder which generates a porousblock. The first binder is typically an organic polymer material, suchas a polyamine, polyacrylamide, polyvinylalcohol, polyacrylic, orpolyelectrolyte derived from natural or synthetic polymers or aninorganic material such as a metal oxide or hydroxide or a polysilane.The second binder employed for the purpose of generating the porousblock is typically a thermoplastic such as polyethylene or material thatgenerates immobilization pressure through fluid absorption.

In a particular aspect of this embodiment, the invention relates to arigid porous block filter that contains a mixture of granulated carbonand apatite derivatives, or granulated activated charcoal (GAC) or bonechar or other adsorptive filter media using a first binder materialwhich is an inorganic, and a second binder, such as a thermoplasticmaterial, such that the mineral materials and derivatives and GAC arefixed within the binder matricies, and that channeling from flow duringwater treatment cannot occur.

The final purification material of the invention can be produced byextrusion, molding including injection molding, or by fluidabsorption/compression methods. Fibrillation may also be used to preparefibrils of the mixture of first binder and mineral and carbonparticulates that can then be formed into a sheet, film, or block. Itmay be produced in any shape or size and may be rigid or flexible.

The pore size of the filter block influences flow rates of the fluidthrough the filter, and is a function of the size of the granularparticles generated in the first step and incorporated into the filterblock in the second step. As used herein, the term “block” does notdenote any particular geometrical shape, but rather that the material isnot a sheet or membrane, or coating. Nonlimiting examples of “blocks” asthis term is intended to be used include tubes, annular rings, as wellas more conventional geometrical solids. Material formed into flexibleblocks is particularly suitable for use in pipes or tubes that serve asthe fluid filter medium.

One of the desirable features of the purification material of theinvention is that it may be formed into any desired shape, and thusprovides ease of handling and use. For example, the purificationmaterial may be formed into a monolith or block that fits intoconventional housings for filtration media or it can be shaped toprovide purification as part of a portable or personal filtrationsystem. Alternatively, the material may be formed into several differentpieces, through which water flows in series or in parallel. Sheets ormembranes of the purification material may also be formed. The rigidityof the purification material, whether in block form or insheet/membrane/coating form, may be altered through inclusion offlexible polymers in the binder material.

While not wishing to be bound by any theory, it is believed that thepurification material of the invention achieves its unusually highefficiency in removing chemicals and microorganisms from fluids partlyas the result of the immobilization of the filtration particles in thebinders, and the necessity for fluid flowing through the purificationmaterial to follow an extended and tortuous path therethrough, insteadof forming channels through the purification material as occurs in priorparticulate-containing purification materials. This path ensures thatthe fluid contacts a larger proportion of the surface area of thefiltration particles, and it prevents sustained laminar flow of thefluid through the filtration material. This latter effect is believed tohelp prevent laminae of fluid containing chemicals and microorganismsfrom avoiding sustained contact with the filtration particles in thefilter. After the purification material has been in service for a periodof time, additional filtration by occlusion will occur as adsorbedmaterial accumulates in the pores of the purification material.

Those familiar with the art of fluid filtration will understand that thepore size and physical dimensions of the purification material may bemanipulated for different applications and that variations in thesevariables will alter flow rates, back-pressure, and the level ofchemical and microbiological contaminant removal. Likewise thoseknowledgeable in the art will recognize that variations in thepercentages of each component of the purification material will providesome variability in utility. For example, increasing the percentage offiltration particulate material in the purification material will resultin a material having an increased number of interaction sites forchemical and biological species, while increasing the percentage of abinder with no active fluid treatment sites will result in apurification material having material and mechanical properties closerto that of the binder material and with reduced interaction sites.

In one particular embodiment of the invention, the mineral material usedis in the form of apatite, and the hydroxyapatite and GAC material arepresent in approximately equal amounts, with the percentage of both thefirst and second binder materials kept to a minimum. However, themineral adsorbents used in the invention may be obtained from othernatural or synthetic/industrial sources and mixtures of the differentderivatives can provide differences in the properties of thepurification material. For example, adding fluoride to the filter blockwill result in a decreased reduction of fluoride in the effluent waterif water is used as the fluid. This can be useful in, e.g. purifyingfluorinated water in such a way as to maintain desirable fluorine levelstherein. Fluoride in the filter material may be obtained either byinclusion of fluoride containing apatite, inclusion of fluoride saltsand compounds, or by pre-conditioning the purification material bypassing fluoride-containing solutions therethrough.

Likewise, as the number of binding sites is increased through the use ofdifferent crystal and material structures and orientation of differentcrystal faces, the binding of metal ions, radioactive isotopes, andmicroorganisms can also be increased. Commonly, exposure to increasedtemperatures allows conversion between crystalline and amorphous forms.Furthermore choosing a first, and or second binder material with activefluid treatment sites such as those which occur with charged anduncharged binders facilitates the “tailoring” of the filtration materialfor specific applications.

Those experienced in the art will also understand that different crystalor amorphous lattices are possible for mineral filtration particles, andfor other adsorbent materials used in the invention, and that thesevariations will yield differences in properties of the resultingpurification material, as certain crystal structures improve and inhibitinteractions with chemicals, microorganisms and other biologicalmaterials. These differences in properties result from differences ininteractions between the chemicals and microorganisms and otherbiological materials and the different positive, negative ions, andneutral species that are included in the crystal structure.

In another embodiment of the invention, the purification material isconstructed to withstand sterilization. Sterilization processes includethermal processes, such as steam sterilization or other processeswherein the purification material is exposed to elevated temperatures orpressures or both, resistive heating, radiation sterilization whereinthe purification material is exposed to elevated radiation levels,including processes using ultraviolet, infrared, microwave, and ionizingradiation, and chemical sterilization, wherein the purification materialis exposed to elevated levels of oxidants or reductants or otherchemical species, and which is performed with chemicals, such ashalogens, reactive oxygen species, formaldehyde, surfactants, metals andgases such as ethylene oxide, methyl bromide, beta-propiolactone, andpropylene oxide.

Additionally, sterilization may be accomplished with electrochemicalmethods by direct oxidation or reduction with microbiological componentsor indirectly through the electrochemical generation of oxidative orreductive chemical species. Combinations of these processes may alsoused. It should also be understood that sterilization processes may beused on a continuous or batch basis while the purification material isin use.

In general, the invention comprises a device and a method for thefiltration and purification of a fluid, in particular an aqueoussolution or water, to remove organic and inorganic elements andcompounds present in the water as particulate material. In particular,the device and method can be used to remove microbiologicalcontaminants, including cysts, bacteria and viruses and componentsthereof, as well as chemical species, such as pesticides and byproductsof chemical treatment processes, from water or other fluids or gassesdestined for consumption or other use by humans or other animals. Themethod and device of the invention are particularly useful in theseapplications where the reduction in concentration of chemical andmicrobiological contaminants made possible by the invention addressesthe EPA standards for microbiological and chemical water purificationdevices, and also significantly exceeds the effectiveness of other knownfiltration and purification devices incorporating granulated adsorptionmedia that contain filtration particulate matter in the absence ofbinder materials.

In a particular embodiment of the invention, the purification materialis a porous block formed by granulated or particulate apatite, oxide, orsilicate material, which is defined herein to include hydroxyapatite,alumina, and iron and/or magnesium containing silicates and otheroptional adsorptive granular materials, described in more detail below,such as granulated activated charcoal (GAC), retained within a multiplepolymer binder matrix. In the method corresponding to this particularembodiment, the microbiological contaminants are removed from the waterwhen the water is forced through the porous block by water pressure onthe influent side, or by a vacuum on the effluent side, of the filterblock.

In an embodiment of the invention where the purification material iscomposed of a mixture of apatite and/or an adsorptive granular filtermedia, for example GAC, such components can be dispersed in a randommanner throughout the block. The purification material can also beformed with spatially distinct gradients or separated layers. Forexample, apatite and alumina and GAC granules may be immobilized inseparate layers using a solid second binder matrix, for instance, apolymer thermoplastic such as polyethylene or the like, so that movementof the mineral particulate and GAC particles is precluded anddetrimental channeling effects during fluid transport through the blockare prevented. If the components reside in separate locations, the fluidflow is sequential through these locations. In a particular example ofthis embodiment, at least a portion of the apatite present originatesfrom synthetic mixtures thereof. An example of a suitable material isthat designated as tricalcium phosphate as sold by Murlin Chemical in PAand/or Brimac Carbon Services, UK, and carbon as provided by KXIndustries in CT. The carbon material may be ground to a desirableparticle size, e.g., 80×325 mesh. A typical analysis of these materialsshows greater than 90% purity. The element binding characteristics ofthese materials have been reported and such elements include chlorine,fluorine, aluminum, cadmium, lead, mercury (organic and inorganic),copper, zinc, iron, nickel, strontium, arsenic, chromium, manganese, andcertain radionuclides. The organic molecule binding capabilities havebeen reported for complex organic molecules, color-forming compounds,compounds that add taste to fluids, compounds that add odors to fluids,and trihalomethane precursors.

In this embodiment, the mineral species (apatite, oxide, hydroxide,silicate, etc.) and the GAC are mixed in approximately equal amountswith the minimal amount of first binder material required to generateparticles in the 80×325 mesh size and the minimum amount of secondbinder necessary to generate a monolithic purification material.However, the amounts of mineral particulate matter, GAC, and binder aresubstantially variable, and materials having different concentrations ofthese materials may be utilized in a similar fashion without the needfor any undue experimentation by those of skill in the art. In general,however, when GAC, or bone char is used as the additional adsorbentmaterial, its concentration in the mixture is generally less than 50% byweight, based upon the weight of the composition before any drying orcompacting. Additionally, adsorbents other than GAC may be substitutedcompletely for, or mixed with, the GAC in a multicomponent mixture.Examples of these adsorbents include various ion-binding materials, suchas synthetic ion exchange resins, zeolites (synthetic or naturallyoccurring), diatomaceous earth, metal hydroxides and oxides, inparticular those containing the metals such as aluminum, calcium,magnesium, and iron and one or more other phosphate-containingmaterials, such as minerals of the phosphate class, in particular,minerals of the aluminosilicate group. In particular, minerals of thealuminosilicate group that contain magnesium, calcium, iron, sodium andor potassium, and mixtures thereof, are particularly suitable for theinvention. These materials may be calcined, sintered, and/or purified byany of the well known mineral processing methods.

Additionally, polymeric materials for ion-binding, including derivatisedresins of styrene and divinylbenzene, and methacrylate, may be used. Thederivatives include functionalized polymers having anion binding sitesbased on quaternary amines, primary and secondary amines, aminopropyl,diethylaminoethyl, and diethylaminopropyl substituents. Derivativesincluding cation binding sites include polymers functionalized withsulfonic acid, benzenesulfonic acid, propylsulfonic acid, phosphonicacid, and/or carboxylic acid moieties. Natural or synthetic zeolites mayalso be used or included as ion-binding materials, including, e.g.,naturally occurring aluminosilicates such as clinoptilolite.

Suitable materials for the first binder which is used to flocculate,coagulate and/or aggregate, small particulate matter into largeparticulate matter may include any material capable of aggregating theparticulate materials together and maintaining this aggregation underthe conditions of use. They are generally included in amounts rangingfrom about 1 wt % to about 99.9 wt %, more particularly from about 15 wt% to about 50 wt %, based upon the total weight of the purificationmaterial. If a polymeric binder material is used it may be chargedpositively, negatively, or uncharged and may originate from syntheticsources or natural sources. Suitable binders include polyamides,polyalcohols, polysaacharides, polyacrylamides, polyacrylates, humicacids, and proteins. Binders may also include materials such as metalhydroxides and oxides including those containing aluminum, calcium,magnesium, and iron and including polyaluminum sulfates and polyaluminumchlorides. Binders appropriate for this first step can includepolorganozirconates, polyorganoaluminates, polysiloxanes, polysilanes,polysilazanes, polycarbosilanes, polyborosilanes, zirconiumdimethacrulate, zirconium tetramethacrylate, zirconium 2-ethylhexanoate,aluminum butoxides, aluminum diisopropoxide ethylacetoacetate,tetramethyldisiloxanes and derivatives thereof,tristrimethylsilylphosphate, and tristrimethylsiloxyboron.

Exempliary first step binders also include polyelectrolytes carryingpositive or negative charged chemical functionalities, or a combinationthereof. These may include but are not limited to polyamines such aspoly(DADMAC), Poly-DADM, Polyamine-Poly(DADMAC) blends, polyquartenaryamines, inorganic-polyamine blends, and inorganic Poly(DADMAC) blends.Additionally, cationic starch, and cationic polymethylmethacrylates maybe used. Also, copolymers of vinylimidazolium methochloride andvinylpyrrolidone, quarternizedvinylpyrrolidone/dimethyl-aminoethyl-methacrylate copolymer, andpolyethyleneimine. Companies manufacturing suitable materials includeVinings Industries, Cytec, BASF Corporation, Ontario Specialty CoatingsCorp., International Specialty Products, and EKA Chemicals.

The primary requirement for the first binder is that it yields theappropriate particle size under the conditions which the second binderis employed for porous solid generation. Those skilled in the art willunderstand that the first binder may be employed through a number ofphysical processing methods including, but not limited to, dripping,spraying, solid state reaction, and solution state reaction. It shouldbe understood by those experienced in the art that step processingmethods may remove portions of the first binder while maintainingappropriate particle size and that processing with the second binder mayremove or displace some of the first binder.

It should also be understood by those experienced in the art of watertreatment that the interactions between insoluble treatment particlesand the first binder may be classified as that of flocculation,coagulation, aggregation and combinations thereof. Additionally, itshould be understood that different binders will react to varyingdegrees with water treatment oxidizers such as chlorine. It should alsobe understood that regulatory agencies such as the US FDA, US EPA, CEN,DWI, and KIWA have regulatory requirements for the concentration ofthese materials that may be present in food stuffs and potable waters.

Suitable materials for the second and other binders which are used togenerate the monolithic porous block include any polymeric materialcapable of aggregating the particulate materials together andmaintaining this aggregation under the conditions of use. They aregenerally included in amounts ranging from about 1 wt % to about 99.9 w%, more particularly from about 15 wt % to about 50 wt %, based upon thetotal weight of the purification material.

Suitable polymeric materials include both naturally occurring andsynthetic polymers, as well as synthetic modifications of naturallyoccurring polymers. The polymeric binder materials generally include oneor more thermoset, thermoplastic, elastomer, or a combination thereof,depending upon the desired mechanical properties of the resultingpurification material.

In general, polymers melting between about 50° C. and about 500° C.,more particularly, between about 75° C. and about 350° C., even moreparticularly between about 80° C. and about 200° C., are suitablepolymeric binders for the invention. For instance, polyolefins meltingin the range from about 85° C. to about 180° C., polyamides melting inthe range from about 200° C. to about 300° C., and fluorinated polymersmelting in the range from about 300° C. to about 400° C., can beparticularly mentioned as suitable. Examples of types of polymerssuitable for use as binders in the invention include, but are notlimited to, thermoplastics, polyethylene glycols or derivatives thereof,polyvinyl alcohols, polyvinylacetates, and polylactic acids. Suitablethermoplastics include, but are not limited to, nylons and otherpolyamides, polyethylenes, including LDPE, LLDPE, HDPE, and polyethylenecopolymers with other polyolefins, polyvinylchlorides (both plasticizedand unplasticized), fluorocarbon resins, such aspolytetrafluoroethylene, polystyrenes, polypropylenes, cellulosicresins, such as cellulose acetate butyrates, acrylic resins, such aspolyacrylates and polymethylmethacrylates, thermoplastic blends orgrafts such as acrylonitrile-butadiene-styrenes oracrylonitrile-styrenes, polycarbonates, polyvinylacetates, ethylenevinyl acetates, polyvinyl alcohols, polyoxymethylene, polyformaldehyde,polyacetals, polyesters, such as polyethylene terephthalate, polyetherether ketone, and phenol-formaldehyde resins, such as resols andnovolacs. Those of skill in the art will recognize that otherthermoplastic polymers can be used in the invention in an analogousmanner.

Suitable thermoset polymers for use as, or inclusion in, the binder usedin the invention include, but are not limited to, polyurethanes,silicones, fluorosilicones, phenolic resins, melamine resins, melamineformaldehyde, and urea formaldehyde. Suitable elasomers for use as orinclusion in, the binder used in the invention include but are notlimited to natural and/or synthetic rubbers, like styrene-butadienerubbers, neoprenes, nitrile rubber, butyl rubber, silicones,polyurethanes, alkylated chlorosulfonated polyethylene, polyolefins,chlorosulfonated polyethylenes, perfluoroelastomers, polychloroprene(neoprene), ethylene-propylene-diene terpolymers, chlorinatedpolyethylene, VITON (fluoroelastomer), and ZALAK® (Dupont-Dowelastomer).

Those of skill in the art will realize that some of the thermoplasticslisted above can also be thermosets, depending upon the degree ofcrosslinking, and that some of each may be elastomers, depending upontheir mechanical properties, and that the particular categorization usedabove is for ease of understanding and should not be regarded aslimiting or controlling. Naturally occurring and synthetically modifiednaturally occurring polymers suitable for use in the invention include,but are not limited to, natural and synthetically modified celluloses,such as cotton, collagens, and organic acids. Biodegradable polymerssuitable for use in the invention include, but are not limited to,polyethylene glycols, polylactic acids, polyvinylalcohols,co-polylactideglycolides, and the like.

In the specific embodiment of a filter material that may be sterilizedthe mineral filtration material originating from natural or syntheticsources and GAC or bone char material are present in approximately equalamounts, with the percentage of binders kept to a minimum. The bindersused must be stable to the temperature, pressure, electrochemical,radiative, and chemical conditions presented in the sterilizationprocess, and should be otherwise compatible with the sterilizationmethod. Examples of first binders can include acrylamides, acrylates,and any stable polyelectrolytes. Examples of second binders suitable forsterilization methods involving exposure to high temperatures (such assteam sterilization or autoclaving) include cellulose nitrate,polyethersulfone, nylon, polypropylene, polytetrafluoroethylene(teflon), and mixed cellulose esters. Purification materials preparedwith these binders can be autoclaved when the binder polymers areprepared according to known standards. Desirably, the purificationmaterial is stable to both steam sterilization or autoclaving andchemical sterilization or contact with oxidative or reductive chemicalspecies, as this combination of sterilizing steps is particularlysuitable for efficient and effective regeneration of the purificationmaterial. Additionally, sterilization and regenerating of devicesincorporating the mineral materials may be conducted by passingsolutions of apatite, alum, acid, and/or caustic through the filter.

In the embodiment of the invention wherein sterilization is at least inpart conducted through the electrochemical generation of oxidative orreductive chemical species, the electrical potential necessary togenerate said species can be attained by using the purification materialitself as one of the electrodes. For example, the purification material,which contains polymeric binder, can be rendered conductive through theinclusion of a sufficiently high level of conductive particles, such asGAC, carbon black, or metallic particles to render a normally insulativepolymeric material conductive. Alternatively, if the desired level ofcarbon or other particles is not sufficiently high to render anotherwise insulative polymer conductive, an intrinsically conductivepolymer may be used as or blended into the binder. Examples of suitableintrinsically conductive polymers include doped polyanilines,polythiophenes, and other known intrinsically conductive polymers. Thesematerials can be incorporated into the binder in sufficient amount toprovide a resistance of less than about 1 kΩ, more particularly lessthan about 300 Ω.

The purification material of the present invention need not be in theform of a block, but may also be formed into a self-supporting sheet orfilm. This sheet or film may, in a particular embodiment, be disposed ona woven or nonwoven web of, e.g., a polymer. The polymer used to formthe woven or nonwoven web may be any thermoplastic or thermosettingresin typically used to form fabrics. Polyolefins, such as polypropyleneand polyethylene, are particularly suitable in this regard.

The purification material of the present invention need not be in theform of a block, or sheet but may also be formed into a coating whichmay be disposed on a porous or nonporous supporting substrate. Thiscoating may, in a particular embodiment, be disposed on a woven ornonwoven web of, e.g., a polymer. The polymer used to form the woven ornonwoven web may be any thermoplastic or thermosetting resin typicallyused to form fabrics. Polyolefins, such as polypropylene andpolyethylene, are particularly suitable in this regard. The coating maybe disposed on a metal surface such as a sheet, fiber, or wire. Suitablemetals include steel, iron containing alloys, precious metals, silver,copper, and gold, and aluminum, and coinage metals. The coating may bedisposed on a metal surface such as a mesh or screen. Suitable meshesinclude those made from steel, iron containing alloys, precious metals,silver, copper, and gold, and aluminum, and coinage metals.

The efficiency of the purification material and the method for using itto reduce chemical and microbiological contaminants and the flow rate ofthe fluid through the material, are a function of the pore size withinthe block and the influent fluid pressure. At constant fluid pressure,flow rate is a function of pore size, and the pore size within the blockcan be regulated by controlling the size of the mineral particulate andGAC granules. For example, a large granule size provides a less dense,more open purification material which results in a faster flow rate, andsmall granule size provides a more dense, less open purificationmaterial which results in a slower flow rate. A block 17 formed withrelatively large filtration particle granules will have less surfacearea and interaction sites than a block formed with smaller granules.Accordingly, the purification material of large granules must be ofthicker dimension to achieve equal removal of microbiologicalcontaminants. Because these factors are controllable within themanufacturing process, the purification materials can be customized byaltering pore size, block volume, block outer surface area, andgeometric shape to meet different application criteria. Average poresize in a particular embodiment is kept to below several microns, andmore particularly to below about one micron, to preclude passage ofcysts. It should be noted that the pore size described herein does notrefer to the pores within the enlarged particles or in the particlescomprising the enlarged particles or other adsorbent particlesthemselves, but rather to the pores formed within the purificationmaterial when the particles are aggregated together by the binder.

The method of making the material of the invention, in its most generalaspect, involves combining the particulate filtration material (andoptional additional particulate adsorbent material(s) with the firstbinder material under conditions of pressure and temperature that allowinteraction between the materials and flocculation, coagulation,agglomeration, or a combination thereof, and a second binder materialunder conditions of pressure and temperature that allow at least aportion of the binder to be present in liquid form and that allow forcompaction of the particulate, and then solidifying the binder aroundand/or between the particles. The precise nature of the productionprocess will depend to a certain extent upon the nature of the bindermaterials.

For example, if the first binder material is supplied in the form of aliquid solution, suspension, or emulsion (e.g., in a volatile solvent),it may be contacted with the particles by dipping or spraying, and thewet particles compressed in a mold. The mold may be optionally heated toevaporate any necessary solvent or binder. The resulting molded materialis then dried to form a purification material which can then be milledto the desired particle size desired for interaction with the secondbinder. The wet material may also be extruded or dewatered and thenprocessed to the desired particle size.

In similar fashion, if the first or second binder material is suppliedin the form of a liquid solution, suspension, or emulsion (e.g., in avolatile solvent), it may be contacted with the particles generated inthe first binding process by dipping or spraying, and the wet particlescompressed in a mold. The mold may be optionally heated to evaporate anynecessary solvent. The resulting molded material is then dried to formthe purification material of the invention.

If, on the other hand, the first or second binders are a polymer resin,it will typically be mixed in pellet form with the particles of theadsorbent material, and the resulting mixture heated and extruded ormolded into the desired shape. Examples of suitable particulate/binderextrusion processes and equipment are disclosed in U.S. Pat. Nos.5,189,092; 5,249,948; and 5,331,037. Other extrusion equipment andprocesses may also be used. Moreover, the mixture may be heated andinjection molded, without the need for any extrusion. Additionally, thebinder, a thermoset, may be generated through a crosslinking processthat incorporates initiation by chemical processes, electrochemicalprocesses, irradiation and through physical parameters of temperatureand pressure variations.

With reference to the drawings, the invention and a mode of practicingit will now be described with regard to one particular embodiment, whichsignificantly exceeds the EPA requirements for microbiological filters.

FIG. 1 illustrates a typical specific embodiment of a filtrationapparatus containing the purification material of the invention, whichincorporates a rigid porous block filter. A removable housing 11 ismated with a cap 12, the cap 12 having an inflow orifice 13 and anoutflow orifice 14. A water supply conduit 15 is joined to the infloworifice 13 to deliver non-treated water into the device, and a waterdischarge conduit 16 is joined to the outflow orifice 14 to conducttreated water from the device. Water passes into the housing 11. Thepressure of the water flow forces it through the porous block filtermember 17, which as shown is formed in the shape of hollow cylinder withan axial bore 18. The treated water then passes into the axial bore 18which connects to the outflow orifice 14. FIG. 2 is provided as arepresentative illustration of one possible configuration. It is to beunderstood that other configurations where water is caused to passthrough a porous filter block (which may have different geometricalshapes and/or different flow properties) are contemplated to be withinthe scope of the invention. The block 17 may be formed by any of anumber of known methods, such as by extrusion, compression, molding,sintering or other techniques.

FIGS. 2 a and 2 b shows two embodiments where the purification materialof the invention is used in the form of a sheet or film. FIG. 2 a showspurification material 1 used in connection with normal flow-throughfiltration, indicated by arrow 2, which represents the fluid beingfiltered by passage through the sheet or film 1. FIG. 2 b showspurification material 1 used in connection with crossflow filtration.Fluid flowing across the filter is indicated by double-headed arrow 3,while fluid flowing through the purification material 1 is indicated byarrow 2. The cross flow fluid indicated by arrow 3 sweeps across thesurface of the purification material 1, decreasing the level ofparticulate matter deposited thereon.

EXAMPLE 1

A cylindrical filter block 17 of the shape shown in FIG. 2 may beprepared with a material composition of approximately 42.5% apatiteobtained from Murlin Chemical in PA in the form ofhydroxycalciumphosphate and approximately 42.5% GAC obtained from KXIndustries. Approximately 10% inorganic binder, selected from one ormore of the inorganics described above, as a first binder is used toincrease the particle size of the hydroxycalciumphosphate and 15%(polyethylene) thermoplastic binder material selected from one or moreof the thermoplastics described above is used as a second binder togenerate the porous block of all components.

The material may be extruded at a temperature that provides a uniformmixture of mineral adsorbent, GAC, aggregating binder and thermoplasticbinder. The cylindrical or toroidally shaped block 17 is approximately9.8 inches in length, with an outer diameter of approximately 2.5 inchesand an inner diameter (the bore 18) of approximately 1.25 inches. Thisshape filter fits into a standard water filtration housing used in thehome and industrial settings. The filter material has a resistance ofabout 300 Ω.

EXAMPLE 2

The filter prepared in Example 1 may be challenged by exposing it to tapwater that is filtered with activated carbon and then seeded with2.3×10⁸ colony forming units per liter of K. terrigena bacteria and1.0×10⁷ units per liter of MS2 virus. The seeded water is passed throughthe filter block 17 at a flow rate of approximately 2 liters/minute for3 minutes, followed by collection of a 500 ml effluent sample. Bacteriamay be assayed on m-Endo agar plates by membrane filtration procedure,while the MS2 virus may be assayed by standard methods.

EXAMPLE 3

The composite prepared in Example 1 may be used to reduce a watersoluble chlorine species such as hypochlorous acid in an oxidized stateto a chlorine species in a reduced state (choride). Chlorine levels ofapproximately 2.0 mg/L were reduced to below the detection limits ofstandard test strip based assays.

As described above, the material of the invention is extremely useful inthe area of water purification, particularly the area of drinking waterpurification. Because of the extremely high efficiency with which thematerial of the present invention removes chemicals and microorganismsfrom water, it meets and exceeds the EPA guidelines for materials usedas microbiological and chemical water purifiers. In addition tofunctioning as a purifier for drinking water, the material of theinvention can also be used to purify water used for recreationalpurposes, such as water used in swimming pools, hot tubs, and spas.

As the result of the ability of the material of the invention toefficiently remove and immobilize microorganisms and other cells fromaqueous solutions, it has numerous applications in the pharmaceuticaland medical fields. For example, the material of the invention can beused to fractionate blood by separating blood components, e.g., plasma,from blood cells, and to remove microorganisms from other physiologicalfluids.

The material can also be used in hospital or industrial areas requiringhighly purified air having extremely low content of microorganisms,e.g., in intensive care wards, operating theaters, and clean rooms usedfor the therapy of immunosuppressed patients, or in industrial cleanrooms used for manufacturing electronic and semiconductor equipment.

The material of the invention has multiple uses in fermentationapplications and cell culture, where it can be used to removemicroorganisms from aqueous fluids, such as fermentation broths orprocess fluids, allowing these fluids to be used more efficiently andrecycled, e.g., without cross-contamination of microbial strains. Inaddition, because the material is so efficient at removingmicroorganisms and at retaining them once removed, it can be used as animmobilization medium for enzymatic and other processing requiring theuse of microorganisms. A seeding solution containing the desiredmicroorganisms is first forced through the material of the invention,and then substrate solutions, e.g., containing proteins or othermaterials serving as enzymatic substrates, are passed through the seededmaterial. As these substrate solutions pass through the material, thesubstrates dissolved or suspended therein come into contact with theimmobilized microorganisms, and more importantly, with the enzymesproduced by those microorganisms, which can then catalyze reaction ofthe substrate molecules. The reaction products may then be eluted fromthe material by washing with another aqueous solution.

The material of the invention has numerous other industrial uses, e.g.,filtering water used in cooling systems. Cooling water often passesthrough towers, ponds, or other process equipment where microorganismscan come into contact with the fluid, obtain nutrients and propagate.Microbial growth in the water is often sufficiently robust that theprocess equipment becomes clogged or damaged and requires extensivechemical treatment. By removing microorganisms before they are able topropagate substantially, the present invention helps to reduce thehealth hazard associated with the cooling fluids and the cost anddangers associated with chemical treatment programs.

Similarly, breathable air is often recycled in transportation systems,either to reduce costs (as with commercial airliners) or because alimited supply is available (as with submarines and spacecraft).Efficient removal of microorganisms permits this air to be recycled moresafely. In addition, the material of the invention can be used toincrease indoor air quality in homes or offices in conjunction with theair circulation and conditioning systems already in use therein.

The purification material of the invention can also be used to purifyother types of gases, such as anesthetic gases used in surgery ordentistry (e.g., nitrous oxide), gases used in the carbonated beverageindustry (e.g., carbon dioxide), gases used to purge process equipment(e.g., nitrogen, carbon dioxide, argon), and/or to remove particles fromsurfaces, etc.

In each of these applications, the method of using the material of theinvention is relatively simple and should be apparent to those of skillin the filtration art. The fluid or gas to be filtered is simplyconducted to one side of a block or sheet of material of the invention,typically disposed in some form of housing, and forced through thematerial as the result of a pressure drop across the purificationmaterial. Purified, filtered fluid or gas is then conducted away fromthe “clean” side of the filter and further processed or used.

The invention having been thus described by reference to certain of itsspecific embodiments, it will be apparent to those of skill in the artthat many variations and modifications of these embodiments may be madewithin the spirit of the invention, which are intended to come withinthe scope of the appended claims and equivalents thereto.

1. A purification material for fluids, wherein the material comprisesinsoluble filtration particles aggregated with a first binder andcombined into the form of a porous block, porous sheet, porous coatingor a non-porous coating using a second binder.
 2. The purificationmaterial of claim 1, wherein the material is in the form of a porousblock.
 3. The purification material of claim 2, wherein the porous blockis rigid.
 4. The purification material of claim 2, wherein the porousblock is flexible.
 5. The purification material of claim 1, wherein thematerial is in the form of a porous sheet.
 6. The purification materialof claim 5, wherein the porous sheet is rigid.
 7. The purificationmaterial of claim 5, wherein the porous sheet is flexible.
 8. Thepurification material of claim 1, wherein the material is in the form ofa porous coating.
 9. The purification material of claim 8, wherein theporous coating is contained on a substrate which is rigid.
 10. Thepurification material of claim 8, wherein the porous coating iscontained on a substrate which is flexible.
 11. The purificationmaterial of claim 1, wherein the material is in the form of a non-porouscoating.
 12. The purification material of claim 11, wherein thenon-porous coating is contained on a substrate which is rigid.
 13. Thepurification material of claim 11, wherein the non-porous coating iscontained on a substrate which is flexible.
 14. The purificationmaterial of claim 1, wherein at least a portion of said insoluble filtermaterial is carbon in a form selected from particles, fibers, or acombination thereof.
 15. The purification material of claim 1, whereinat least a portion of said insoluble filtration material is derived fromminerals containing apatites, phosphates, silicates, hydroxides, oxidesor combinations thereof.
 16. The purification material of claim 1,wherein the first binder is a polymer material.
 17. The purificationmaterial of claim 16, wherein the first binder is a polymer materialcontaining positive charges, negative charges, hydrogen bonding sites,or a combination thereof.
 18. The purification material of claim 17,wherein the first binder is a polyelectrolyte material derived fromnatural polymers or modified natural polymers.
 19. The purificationmaterial of claim 18, wherein the first binder is a polyelectrolytematerial known as cationic starch.
 20. The purification material ofclaim 17, wherein the first binder is a polyelectrolyte materialselected from the group consisting of polyamines, polyamides,polyalcohols, polysaacharides, polyacrylamides, polyacrylates, humicacids, proteins, poly(DADMAC), Poly-DADM, polyamine-poly(DADMAC) blends,polyquartenary amines, inorganic-polyamine blends, and inorganicPoly(DADMAC) blends, cationic starch, cationic polymethylmethacrylates,copolymers of vinylimidazolium methochloride and vinylpyrrolidone,quarternized vinylpyrrolidone/dimethyl-aminoethyl-methacrylatecopolymer, and polyethyleneimine.
 21. The purification material of claim1, wherein the first binder is selected from the group consisting ofmetal hydroxides and oxides.
 22. The purification material of claim 21,wherein the first binder is selected from the group containing aluminum,calcium, magnesium, iron, polyaluminum sulfates, polyaluminum chlorides,polyorganozirconates, polyorganoaluminates, polysiloxanes, polysilanes,polysilazanes, polycarbosilanes, polyborosilanes, zirconiumdimethacrulate, zirconium tetramethacrylate, zirconium 2-ethylhexanoate,aluminum butoxides, aluminum diisopropoxide ethylacetoacetate,tetramethyldisiloxanes and derivatives thereof,tristrimethylsilylphosphate, and tristrimethylsiloxyboron.
 23. Thepurification material of claim 21, wherein the first binder is a metaloxide or hydroxide derived from aluminum, calcium, magnesium, or iron.24. The purification material of claim 1, wherein the second binder is apolymer material.
 25. The purification material of claim 24, wherein thebinder is a polymer melting between about 50° C. and about 500° C. 26.The purification material of claim 24, wherein the polymer is stableunder sterilization conditions.
 27. The purification material of claim24, wherein said binder is selected from the group consisting ofthermoplastics, polyethylene glycols or a derivative thereof, polyvinylalcohols, polyvinylacetate, and polylactic acids.
 28. The purificationmaterial of claim 24, wherein the polymer material is a thermoplastic isselected from the group consisting of nylon, polyethylene,polyvinylchloride, fluorocarbon resins, polystyrene, polypropylene,cellulosic resins, and acrylic resins.
 29. The purification material ofclaim 24, wherein the polymer material comprises a naturally occurringpolymer.
 30. The purification material of claim 29, wherein thenaturally occurring polymer is selected from the group consisting ofnatural and synthetically modified celluloses, collagens, and organicacids.
 31. The composite purification material of claim 29, wherein thenaturally occurring polymer is selected from the group consisting ofnatural and synthetically modified celluloses, collagens, and organicacids.
 32. The composite purification material of claim 29, wherein thenaturally occurring polymer is a biodegradable polymer selected from thegroup consisting of a polyethyleneglycol, a polylactic acid, apolyvinylalcohol, a co-polylactideglycolide, cellulose, alginic acids,carrageenans isolated from seaweeds, polysaccharides, pectins, xanthans,starch, and combinations thereof.
 33. The purification material of claim24, wherein the polymer material comprises an electrically conductivepolymer.
 34. The purification material of claim 24, wherein the polymermaterial comprises a biodegradable polymer.
 35. The purificationmaterial of claim 34, wherein the biodegradable polymer is apolyethyleneglycol, a polylactic acid, a polyvinylalcohol, or aco-polylactideglycolide.
 36. The purification material of claim 24,wherein said binder is selected from the group consisting of gelling orabsorbent materials.
 37. The purification material of claim 36, whereinsaid binder is selected from the group consisting of superabsorbents.38. The composite purification material of claim 37, wherein saidsuperabsorbent comprises a material selected from polyacrylic acids,polyacrylamides, poly-alcohols, polyamines, polyethylene oxides,cellulose, chitins, gelatins. starch, polyvinyl alcohols and polyacrylicacid, polyacrylonitrile, carboxymethyl cellulose, alginic acids,carrageenans isolated from seaweeds, polysaccharides, pectins, xanthans,poly-(diallyldimethylammonium chloride), poly-vinylpyridine,poly-vinylbenzyltrimethylammonium salts, polyvinylacetates, polylacticacids or a combination thereof.
 39. The composite purification materialof claim 37, wherein the superabsorbent material comprises an ionicallycharged surface.
 40. The composite purification material of claim 37,wherein the superabsorbent material comprises a biodegradable polymer.41. The purification material of claim 37, wherein said binder isselected from the group consisting polylactic acids, polyacrylamides orcombinations of the polymers thereof.
 42. The composite purificationmaterial of claim 37, wherein the absorbent material comprises a clay oraluminosilicate material.
 43. The composite purification material ofclaim 42, wherein the absorbent material comprises is bentonite.
 44. Thecomposite purification material of claim 24, wherein the superabsorbentcomprises a material selected from the group consisting of resinsobtained by polymerizing acrylic acid and resins obtained bypolymerizing acrylamide.
 45. The composite purification material ofclaim 24, wherein the polymer material comprises a naturally occurringpolymer, cellulose, alginic acids, carrageenans isolated from seaweeds,polysaccharides, pectins, xanthans, starch, or combinations thereof. 46.The composite purification material of claim 24, wherein thesuperabsorbent material comprises an ionically charged surface rangingfrom 1-100% of the material surface.
 47. The purification material ofclaim 6, wherein the purification material is in the form of a sheet andis disposed on a woven web.
 48. The purification material of claim 6,wherein the purification material is in the form of a sheet and isdisposed on a nonwoven web.
 49. The purification material of claim 7,wherein the purification material is in the form of a sheet and isdisposed on a woven web.
 50. The purification material of claim 7,wherein the purification material is in the form of a sheet and isdisposed on a nonwoven web.
 51. The purification material of claim 8,wherein the purification material is in the form of a coated substrateand the substrate is rigid.
 52. The purification material of claim 51,wherein the substrate is a metal.
 53. The purification material of claim52, wherein the substrate is a coinage metal.
 54. The purificationmaterial of claim 52, wherein the substrate contains iron.
 55. Thepurification material of claim 51, wherein the substrate is a polymer.56. The purification material of claim 24, wherein the polymer isderived from synthetic sources.
 57. The purification material of claim56, wherein the synthetic source produces a woven substrate.
 58. Thepurification material of claim 24, wherein the synthetic source producesa non-woven substrate.
 59. The purification material of claim 24,wherein the polymer is derived from natural sources.
 60. Thepurification material of claim 59, wherein the natural source produces awoven substrate.
 61. The purification material of claim 59, wherein thenatural source produces a non-woven substrate.
 62. The purificationmaterial of claim 8, wherein the purification material is in the form ofa coated substrate and the substrate is flexible.
 63. The purificationmaterial of claim 62, wherein the polymer is derived from syntheticsources.
 64. The purification material of claim 63, wherein thesynthetic source produces a woven substrate.
 65. The purificationmaterial of claim 63, wherein the synthetic source produces a non-wovensubstrate.
 66. The purification material of claim 62, wherein thepolymer is derived from natural sources.
 67. The purification materialof claim 66, wherein the natural source produces a woven substrate. 68.The purification material of claim 66, wherein the natural sourceproduces a non-woven substrate.
 69. The purification material of claim51, wherein the substrate conducts electricity.
 70. The purificationmaterial of claim 62, wherein the substrate conducts electricity. 71.The purification material of claim 1, wherein the binders are present inan amount ranging from about 1 wt % and about 99.9 wt % of the totalweight of the purification material.
 72. The purification material ofclaim 1, further comprising one or more additional non-carbon adsorptivematerials.
 73. The purification material of claim 72, wherein saidadditional adsorptive material comprises a calcium or magnesiumcontaining phosphate or a calcium or magnesium containing silicate. 74.The purification material of claim 72, wherein said adsorptive materialcomprises apatite obtained from bone char.
 75. The purification materialof claim 72, wherein said adsorptive material comprises an aluminumcontaining silicate, oxide, or hydroxide.
 76. The purification materialof claim 72, wherein said adsorptive material comprises a magnesiumcontaining hydroxide, oxide, or silicate.
 77. The purification materialof claim 72, wherein said additional adsorbent material and saidinsoluble filtration particles are present in approximately equalamounts, further wherein the insoluble filtration particles comprisegranulated activated carbon.
 78. The purification material of claim 77,wherein said additional adsorbent material and said granulated activatedcharcoal are each present in amounts of about 42.5 wt %, and saidbinders are present in an amount of about 15 wt %, based upon the totalweight of said purification material.
 79. The purification material ofclaim 72, wherein said additional adsorptive material comprises anion-binding material selected from the group consisting of synthetic ionexchange resins, zeolites, and phosphate minerals.
 80. The purificationmaterial of claim 79, wherein the phosphate minerals are members of thephosphate class of minerals.
 81. The purification material of claim 79,wherein the phosphate minerals are members of the aluminosilicate groupof minerals.
 82. The purification material of claim 79, wherein thesynthetic ion exchange resins are functionalized styrenes,vinylchlorides, divinyl benzenes, methacrylates, acrylates, andmixtures, copolymers, and blends thereof.
 83. The purification materialof claim 79 wherein the natural or synthetic zeolites are silicatecontaining minerals known as clinoptilolite.
 84. The purificationmaterial of claim 1, further comprising one or more materials thatundergo an chemical oxidation or a chemical reduction in the presence ofwater or aqueous fluid.
 85. A device for filtering microbiologicalcontaminants from water or aqueous fluid, comprising: a housing; and aporous block of the purification material of claim
 1. 86. The deviceaccording to claim 85, wherein the housing comprises an inlet, anoutlet, and a contacting chamber therebetween, and wherein said porousblock is disposed within the contacting chamber, such that fluid canflow into the housing from the inlet passes through the porous block andthen can flow out of the housing through the outlet.
 87. A method forfiltering a fluid to remove any microorganisms therefrom, comprisingcausing the fluid to flow through the purification material of claim 1,thereby obtaining filtered fluid.
 88. The method of claim 87, whereinsaid fluid is water.
 89. The method of claim 89, wherein the filteredwater is potable.
 90. The method of claim 87, wherein said fluid is anaqueous solution.
 91. The method of claim 90, wherein said aqueoussolution is blood.
 92. The method of claim 90, wherein said aqueoussolution is a fermentation broth.
 93. The method of claim 90, whereinsaid aqueous solution is a recycled stream in a chemical or biologicalprocess.
 94. The method of claim 90, wherein the aqueous solution is arecycled stream in a cell culturing process.
 95. The method of claim 90,wherein the aqueous solution has been used in a surgical procedure. 96.The method of claim 87, wherein the fluid comprises breathable air. 97.The method of claim 87, wherein the fluid comprises a purge gas.
 98. Themethod of claim 97, wherein the purge gas is selected from the groupconsisting of O₂, CO₂, N₂, or Ar.
 99. The method of claim 87, whereinthe fluid is an anesthetic gas.
 100. The method of claim 99, wherein theanesthetic gas comprises nitrous oxide.
 101. The method of claim 87,further comprising regenerating said purification material bysterilization.
 102. The method of claim 101, wherein said sterilizationcomprises exposing the purification material to elevated temperature,pressure, radiation levels, or chemical oxidants or reductants, or acombination thereof.
 103. The method of claim 101, wherein saidsterilization comprises autoclaving.
 104. The method of claim 101,wherein said sterilization comprises electrochemical treatment.
 105. Themethod of claim 101, wherein said sterilization comprises a combinationof chemical oxidation and autoclaving.
 106. The method of claim 87,wherein said fluid is a gaseous mixture.
 107. The method of claim 106,wherein the filtered gas is air.
 108. The method of claim 87, whereinsaid fluid is a chemically unreactive gas.
 109. The method of claim 87,wherein said gas is oxygen, carbon dioxide, nitrogen, argon, or nitrogenoxides.
 110. The method of claim 87, wherein said gas is used topressurize a chamber.
 111. The method of claim 87, wherein said gas isused to sparge or purge an aqueous solution for the purpose ofincreasing the concentration of the sparging gas in the solution. 112.The method of claim 87, wherein said gas is used to sparge or purge anaqueous solution for the purpose of decreasing the concentration of thegases initially present in the solution.
 113. The method of claim 87,wherein said gas is used to remove particulate material from surfaces.114. An immobilization and contacting medium for microorganisms,comprising magnesium containing mineral and a binder therefor, themedium in the form of a rigid, porous block or a sheet.
 115. Theimmobilization and contacting medium of claim 114, further comprisingone or more microorganisms disposed within the pores thereof.
 116. Theregeneration of the material of claim 1 through the use of solutionscomprising salt, acid, or caustic.
 117. A method for filtering a fluidto remove any microorganisms therefrom, comprising causing the fluid toflow over the purification material of claim 11, thereby obtainingfiltered fluid.